Food compositions having high solids content, such as confectionery products, e.g. soft candies or wine gum, are conventionally gelled by the use of gelatine, a heterogenous mixture of water-soluble high molecular weight proteins. Gelatine is derived from collagen, usually by boiling anal hides or bones.
Despite its excellent gelling capability, gelatine suffers from a number of drawbacks which can be attributed to its animal origin. Thus, gelatine is unacceptable to those of Muslim and Jewish faith, as it is often prepared from swine skin. Further, recently the use of gelatine in foods has been questioned due to the possible link between consumption of foods containing gelatine of bovine origin and the occurrence of the Creutzfeldt-Jakob disease. Finally, the consumption of animals and animal-derived foods may be objectionable for some from an ethical point of view.
There is therefore a need for a vegetable alternative to gelatine.
One such alternative is carrageenan. Carrageenans extracted from seaweed are known to be useful as thickening, viscosifying and gelling agents. Carrageenans are polysaccharides consisting of alternating copolymers of β(1→3)-D-galactose and α(1→4)-3,6-anhydro-D-galactose units. Several members of the carrageenan family are known, differing in their amounts of sulfate ester and/or other substituent groups, viz iota carrageenan, kappa carrageenan and lambda carrageenan, of which only iota and kappa carrageenans have gelling properties.
A general formula for carageenan is disclosed by Nijenhuis, K. in Advanced Polymer Science, 130, 203–18, (1997): Idealised AB repeating unit of iota and kappa carrageenan polymers based on 1,3-linked β-D-galactose residue (A) and 1,4-linked 3,6-anhydro-α-D-galactose residue (B). The sequence is broken occasionally by residues of the general type B′.
Stortz, C. A. and Cerezo, A. S. describe in Carbohydrate Research, 145 (1986), 219–235, the different members of the carrageenan family by their idealised repeating units:
Carrageenan3-linked residue4-linked residueBetaBeta-D-galactopyranose 4-sulfate3,6-anhydro-alpha-D-galactopyranoseKappaBeta-D-galactopyranose 4-sulfate3,6-anhydro-alpha-D-galactopyranoseIotaBeta-D-galactopyranose 4-sulfate3,6-anhydro-alpha-D-galactopyranose2-sulfateMuBeta-D-galactopyranose 4-sulfateAlpha-D-galactopyra-nose 6-sulfateNuBeta-D-galactopyranose 4-sulfateAlpha-D-galactopyra-nose 2,6-disulfateLambdaBeta-D-galactopyranose 2-sulfateAlpha-D-galactopyra-(70%) and Beta-D-galactopyranosenose 2,6-disulfate(30%)ThetaBeta-D-galactopyranose 2-sulfate3,6-anhydro-alpha-D-galactopyranose-2-sul-fateXiBeta-D-galactopyranose 2-sulfateAlpha-D-galactopyra-nose 2-sulfateHowever, it is well-known to anyone skilled in the art that the solubility of carrageenans in systems of high soluble solids content is very limited, see e.g. “Carrageenan” by W. R. Thomas in Thickening and Gelling Agents for Food, Ed. A. Imeson, 1992, from which it appears that iota carrageenan is insoluble at soluble solids contents of 50% and above, whereas kappa carrageenan is only hot soluble at 50% soluble solids (SS) content. Consequently, carrageenans have in the past mainly been used either in lower SS systems or in systems not requiring any gel formation.
U.S. Pat. No. 5,631,034 discloses a method for preparing an aqueous sugar frosting mix comprising from about 70 to about 90% by weight of sugar, from about 9 to about 29% by weight of aqueous liquid and from about 0.05 to about 1.0% by weight of a crystal growth inhibitor. Said crystal growth inhibitor may be a carrageenan. The purpose of the use of carrageenan in this system is to inhibit crystal growth of the sugar and to provide binding properties of the sprayable solution.
U.S. Pat. No. 5,306,519 discloses a syrup composition having a sufficiently low viscosity so that it can be poured or pumped yet upon contact with a calcium containing confection its viscosity increases. Said syrup comprises from about 25 to about 60% sugar solids, water, at least one sequestrant, and an amount of at least one calcium reactive gum sufficient to thicken the syrup upon contact with the calcium containing confection. Said calcium reactive gum may be a carrageenan which may be incorporated into the syrup at a level from about 0.05 to about 0.5%, preferably from about 0.1 to 0.3%.
WO 95/12985 discloses an injectable fondant and method of manufacturing same. Said injectable fondant presents in its cooled state, at least 0,5 day after manufacture, a solids content of 68–75% by weight, including less than 1% by weight of stabiliser. Said stabiliser may be a carrageenan.
U.S. Pat. No. 5,607,716 discloses a low or no fat, water and sugar based high solid confection comprising at least 80% to 90% total solids by weight, wherein the carbohydrate content is at least 70% by weight of the total solids, a cation containing edible material, a cation reactive and thermosensitive hydrocolloid, and up to 7% by weight of fat, said confection having a water activity below 0.65 and a pH from 3.0 to 8.5. The hydrocolloid may be a carrageenan in an amount of from 0.25 to 3.5% by weight.
U.S. Pat. No. 5,132,128 discloses a dessert topping having a pH greater than 4,6 and having a water activity of less than 0,84 and comprising a blend of carrageenan gum, a powdered cellulose bulking agent, a non-heat thinning cellulose gum bulking agent, high fructose corn syrups, an edible humectant and non-fat milk. The carrageenan gum may be used in an amount in the range of 0.75–1.75% by weight of said topping, and the high fructose corn syrup is in the range of 50–60% by weight of said topping. Said blend of carrageenan gum provides both gelling and viscosity control in order to obtain a suitable low viscosity upon heating while providing a viscous texture of the topping when placed on a dessert, particularly ice cream.
EP 0 045 522 A2 discloses edible food containers for use with a food product by applying a barrier coating composition to at least the interior surface thereof. The barrier coating composition comprises a sugar solution having a sugar content of at least 50% by weight and optionally other ingredients % such as a flavour-producing material or a vegetable gum. Said gum material, which may be a carrageenan, may be present in an amount of about 0.1 to 2% by weight. The barrier coating composition forms a film, which through the use of said gum material adheres to the inner surface of the food container.
EP 0 366 248 A2 discloses preservative compositions for fruits and vegetables comprising antidiscolouration agent and edible thixotropic gum. A typical composition may contain 20–60% by weight of edible bulk filler (eg maltodextrin, preferably a low dextrose equivalent maltodextrin), 20–60% ascorbic acid and 1–50% edible thixotropic gum and 1–25% natural or artificial flavouring. Thus, a thixotropic material is provided.
WO 98/20860 discloses a chewable composition for delivery of a pharmacologically active material to a user comprising sweetener, carrageenan and water, said composition comprising from about 50 to about 83% of solids. Carrageenan may be present in an amount from about 2% to 5,5% and optionally one or more of an additional hydrocolloid is present in a total amount of from about 0.5% to about 2%. Any suitable sweetener may be used.
EP 0 273 001 discloses a soft, sugarless, aerated confectionery comprising soluble solids in the form of hydrogenated starch hydrolysates in the range from 35 to 89% by weight and up to 5.5% by weight of hydrocolloid such as a seaweed extract. The disclosed confectionery does not include any sugar and is deposited at temperatures of about 130 to 140° C.
U.S. Pat. No. 5,603,979 discloses a method for the preparation of a fat-free peanutbutter like product comprising 15–40% by weight of water, 0.5–1.5% by weight of natural gum, 5–20% by weight of peanut flour, 20–35% by weight of syrup and 5–13% by weight of humectant. Carrageenan may be used as gum component. The product obtained must be spreadable.
Thus, as can be seen, the prior use of carrageenan has either been in lower soluble solids systems or in non-gelled end-products. Alternatively, the application of high operating temperatures have been required. It has hitherto not been possible to disperse efficiently a carrageenan in a high solids system at a temperature of below 100° C. at atmospheric pressure in order to form a gelled end-product, in which said carrageenan provides the main gel structure and texture.